The present embodiments relate to an improved x-ray system and an improved collimator having a DAP measurement chamber.
Within the field of medicine, x-rays are mainly used to determine anomalies inside the body, which enable a diagnosis in conjunction with symptoms, signs and possibly other examinations. The various tissue densities in the human or animal body absorb the x-ray beams with differing strengths so that an image of the inside of the body is achieved (e.g., shading, lightening and other x-ray signs).
The problem with using x-ray radiation during therapy and diagnosis is that x-rays behave in a cancer-producing fashion. Various endeavors therefore exist for reducing the x-ray radiation, to which a patient is exposed, to the necessary level but still allowing a high quality image to be produced. Various legislative bodies stipulate the determination of the dose area product (DAP) for each x-ray procedure implemented.
In the prior art, the DAP measurement chamber is arranged in the radiation path between the collimator unit and the patient, frequently as retrofit equipment to the x-ray systems, which were installed prior to the DAP stipulations by the various legislative bodies.
If, however, the x-ray system is equipped with a device for pre-displaying the beam entry field adapted to the purpose of the examination (e.g., a light-beam localizer), the localizer light also passes through and is attenuated in the DAP measurement chamber. As a result, stronger light sources are used for the light-beam localizer, and/or certain light sources (e.g., LEDs) cannot be used since typical DAP chambers have a transmission level of 70% or less (i.e., 30% or more of the visible localizer light is absorbed).